Prediction of fatty acid content in rabbit meat and discrimination between conventional and organic production systems by NIRS methodology

Fatty Acid Profiles and Nutritional Evaluation of Fresh Sweet-Waxy Corn from Three Regions of China

Fresh corn is a kind of herbaceous plant with rich nutritive value and a reasonable composition of fatty acids; however, there is little research on methods for the systemic nutritional evaluation of fatty acids in fresh corn. The aim of the present study was to conduct a comparative analysis of the fatty acid profiles of Chinese Huangnuo 9 sweet-waxy corn from the provinces of Inner Mongolia, Jilin, and Heilongjiang by gas chromatography; to establish a nutritional evaluation system according to the impacts of nutrients from fatty acids on human health; and finally, to evaluate, compare and rank fresh sweet-waxy corn grown in different regions. Tocopherols were detected by liquid chromatography in order to demonstrate the anti-oxidation activity of fresh corn’s fatty acids. The fatty acid contents and compositions of the 12 samples from the three regions are significantly different from each other. The nutrient value of the fatty acids in fresh corn was analyzed by factor analysis and a linear structural relation model, followed by the fitting and appraising of the model. The studied fresh sweet-waxy corn 1-4 from Inner Mongolia had the highest γ-tocopherol content and the closest saturated fatty acid:monounsaturated fatty acid:polyunsaturated fatty acid rate to the recommended value. The fatty acid profiles of sweet-waxy corns 2-1, 2-2, and 2-3 were the most diverse, and the comprehensive evaluation result of fresh corn 2-4 was the best; its total fatty acid content was the highest. Fresh corn 3-1 in Heilongjiang had the highest unsaturated fatty acids and lower values in its atherosclerosis index and thrombosis index, which suggested the strongest anti-atherosclerosis and anti-thrombotic ability. This work will give a reference to guide dietary choices and provide data support for dietary recommendations for residents.

Identification of key genes and functional enrichment pathways involved in fat deposition in Xinyang buffalo by WGCNA

The Xinyang buffalo is a valuable and endangered domestic heritage resource in the Dabie Mountain region in China. With the increasing mechanization of agriculture, the Xinyang buffalo, mainly used for labor, faces unprecedented challenges. One of the feasible approaches to conserve and expand the species is to transfer Xinyang buffalo from service-use to meat-use, but the main hindrance to this transformation is the inferior meat quality of Xinyang buffalo, which is not popular with consumers. Based on the above, this study was conducted to evaluate the growth performance (n = 120) and slaughter performance (n = 3) of Xinyang buffalo and to measure the amino acid levels of the eye muscle (EM), and assess the meat quality. Later, transcriptome sequencing was performed on the subcutaneous fat of the back at six (n = 3) and 30 months of age (n = 3), together with the excavation of candidate genes associated with fat deposition using the weighted co-expression network analysis (WGCNA) method. The results showed that the slaughter rate of Xinyang buffalo was 43.09%, net meat percentage was 33.04%, the ocular area was 59.16 ± 7.58, the backfat thickness was 1.03 ± 0.16, and meat bone ratio was 3.29. The total amino acid contents were 0.63 g per gram of beef, which contained 0.05 g of essential amino acids, and the three most abundant amino acids were Ser (447.17 mg/g), Asp (29.8 mg/g), and Pro (27.24 mg/g). The WGCNA results showed that six phenotypes measured were significantly correlated with the turquoise module (r > 0.97, P < 0.001), and the genes in these modules were significantly enriched in the pathways related to substance metabolism and energy metabolisms, such as metabolic pathways, citrate cycle, and fatty acid metabolism. Meanwhile, six key candidate genes (FH, MECR, GPI, PANK3, ATP6V1A, PHYH) were identified, which were associated with growth and development, fat deposition, and intra-muscular amino acid levels (P < 0.05). In short, this study provides another feasible way to preserve buffalo and enriches the theory of its molecular genetic breeding.

Feasibility of near infrared transmittance spectroscopy to predict fatty acid composition of commercial processed meat

BACKGROUND

The new European Regulation 1169/2011 concerning nutrition declaration of food products compels the addition of saturated fatty acids, whereas the declaration of monounsaturated and polyunsaturated fatty acids remains voluntary. Therefore, the industry is interested in a more rapid, easy and less cost-effective analysis method for accomplishing this labelling regulation. The present study aimed to evaluate the ability of near infrared transmittance spectroscopy (wavelengths between 850 and 1050 nm) to predict the fatty acid (FA) composition of commercial processed meat samples (n = 310).

RESULTS

Good predictions were achieved for the absolute content of saturated, unsaturated, monounsaturated and polyunsaturated FA, as well as ω-6 groups, and also for a few individual FA (C16:0, C18:0, C18:1n9, C18:2n6 and 18:1n7), with the coefficient of determination in cross-validation being > 0.90 and the residual prediction deviation being > 3.15. Unsatisfactory models were obtained for the relative content of FA.

CONCLUSION

Near infrared transmittance spectroscopy can be considered as a reliable method for predicting the main groups of FA in processed meat products, whereas predictions of individual FA are less reliable. © 2017 Society of Chemical Industry.

Applications of near-infrared spectroscopy in food safety evaluation and control: a review of recent research advances

Food safety is a critical public concern, and has drawn great attention in society. Consequently, developments of rapid, robust, and accurate methods and techniques for food safety evaluation and control are required. As a nondestructive and convenient tool, near-infrared spectroscopy (NIRS) has been widely shown to be a promising technique for food safety inspection and control due to its huge advantages of speed, noninvasive measurement, ease of use, and minimal sample preparation requirement. This review presents the fundamentals of NIRS and focuses on recent advances in its applications, during the last 10 years of food safety control, in meat, fish and fishery products, edible oils, milk and dairy products, grains and grain products, fruits and vegetables, and others. Based upon these applications, it can be demonstrated that NIRS, combined with chemometric methods, is a powerful tool for food safety surveillance and for the elimination of the occurrence of food safety problems. Some disadvantages that need to be solved or investigated with regard to the further development of NIRS are also discussed.

Determination of omega-3 fatty acids in fish oil supplements using vibrational spectroscopy and chemometric methods

The potential of Fourier transform infrared (FT-IR), near-infrared (NIR), and Raman spectroscopic techniques combined with partial least squares (PLS) regression (PLSR) to predict concentrations of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and total omega-3 fatty acids (n-3 FAs) in fish oil supplements was investigated. FT-IR spectroscopy predicted EPA (coefficient of determination (R(2)) of 0.994, standard error of cross-validation (SECV) of 2.90%, and standard error of prediction (SEP) of 2.49%) and DHA (R(2) = 0.983, SECV = 2.89%, and SEP = 2.55%) with six to seven PLS factors, whereas a simpler PLS model with two factors was obtained for total n-3 FAs (R(2) = 0.985, SECV = 2.73%, and SEP = 2.75%). Selected regions in the NIR spectra gave models with good performances and predicted EPA (R(2) = 0.979, SECV = 2.43%, and SEP = 3.11%) and DHA (R(2) = 0.972, SECV = 2.34%, and SEP = 2.60%) with four to six PLS factors. Both the whole and selected NIR regions gave simple models (two PLS factors) with similar results (R(2) = 0.997, SECV = 2.18%, and SEP = 1.60%) for total n-3 FAs. The whole and selected regions of Raman spectra provided models with comparable results and predicted EPA (R(2) = 0.977, SECV = 3.18%, and SEP = 2.73%) and DHA (R(2) = 0.966, SECV = 3.31%, and SEP = 2.56%) with seven to eight PLS factors, whereas a simpler model (three PLS factors) with R(2) = 0.993, SECV = 2.82%, and SEP = 3.27% was obtained for total n-3 FAs. The results demonstrated that FT-IR, NIR, and Raman spectroscopy combined with PLSR can be used as simple, fast, and nondestructive methods for quantitative analysis of EPA, DHA, and total n-3 FAs. FT-IR and NIR spectroscopy, in particular, have the potential to be applied in process industries during production of fish oil supplements.

Analytical authentication of organic products: an overview of markers

Consumers' interest in organic foods is increasing and so is the need for robust analytical tools for their authentication. This review focuses on the most promising biomarkers/analytical approaches that are available for the authentication of organic produce. Food products have been subdivided into two groups: foods of plant origin (crops) and foods of animal origin (meat, milk and dairy products, eggs and fish). For each food category the most suitable biomarkers are presented and their potential for authentication is discussed. In the light of current knowledge, it is unlikely that the authentication of organic food products can be attained by the measurement of a single marker. Analytical approaches based on the measurement of multiple markers and/or complex chemical or physical profiles/fingerprints supported by multivariate statistical analysis seem considerably more promising in this respect. For the development of robust classification models, well-designed experimental studies must be performed that rely on data sets that are both well balanced and of sufficient size to ensure that all relevant sources of variation for the target biomarkers are included in the reference database.

Application of NIRS for predicting fatty acids in intramuscular fat of rabbit

The aim of this study was to evaluate the use of near infrared reflectance spectroscopy (NIRS) for predicting fatty acid content in intramuscular fat to be applied in rabbit selection programs. One hundred and forty three freeze-dried Longissimus muscles (LM) were scanned by NIRS (1100-2498nm). Modified Partial Least Squares models were obtained. Equations were selected according to standard error of cross validation (SECV) and coefficient of determination of cross validation (R(2)(CV)). Residual predictive deviation of cross validation (RPD(CV)) was also studied. Accurate predictions were reported for IMF (R(2)(CV)=0.98; RPD(CV)=7.57), saturated (R(2)(CV)=0.96; RPD(CV)=5.08) and monounsaturated FA content (R(2)(CV)=0.98; RPD(CV)=6.68). Lower accuracy was obtained for polyunsaturated FA content (R(2)(CV)=0.83; RPD(CV)=2.40). Several individual FA were accurately predicted such as C14:0, C15:0, C16:0, C16:1, C17:0, C18:0, C18:1 n-9, C18:2 n-6 and C18:3 n-3 (R(2)(CV)=0.91-0.97; RPD(CV)>3). Long chain polyunsaturated FA and C18:1 n-7 presented less accurate prediction equations (R(2)(CV)=0.12-0.82; RPD(CV)<3).

Identification of cattle, llama and horse meat by near infrared reflectance or transflectance spectroscopy

Visible and near infrared reflectance spectroscopy (VIS-NIRS) was used to discriminate meat and meat juices from three livestock species. In a first trial, samples of Longissimus lumborum muscle, corresponding to beef (31) llamas (21) and horses (27), were homogenised and their spectra collected in reflectance (NIRSystems 6500 scanning monochromator, in the range of 400-2500 nm). In the second trial, samples of meat juice (same muscle) from the same species (20 beef, 19 llama and 19 horse) were scanned in folded transmission (transflectance). Discriminating models (PLS regression) were developed against "dummy" variables, testing different mathematical treatments of the spectra. Best models indentified the species of almost all samples by their meat (reflectance) or meat juice (transflectance) spectra. A few (three of beef and one of llama, for meat samples; one of beef and one of horse, for juice samples) were classified as uncertain. It is concluded that NIRS is an effective tool to recognise meat and meat juice from beef, llama and horses.

Organic and conventional Coffea arabica L.: a comparative study of the chemical composition and physiological, biochemical and toxicological effects in Wistar rats

Differentiation between organic and conventional coffee has increased due to the growing demand and high consumption of healthy foods that contain compounds with antioxidant potential, which have been associated with the reduction of chronic diseases. We used organic and conventional coffee in powder 4% (w/w) and infusions 5%, 10% and 20% (w/v) incorporated in a commercial diet to test in vivo. The levels of chlorogenic acid, caffeine and trigonelline were determined by high performance liquid chromatography. The body weight, weight gain, food consumption, aberrant foci crypt, mucin depleted foci, stress biomarkers protein carbonyl and malondialdehyde, biochemical parameters and behavior of the rats were compared between the experimental and control groups within a framework of colon carcinogenesis. The organic coffee showed higher levels of chlorogenic acid, caffeine and trigonelline than conventional, however, this difference did not significantly affect behavior. The infusions had an antioxidant effect, reducing the levels of malondialdehyde; however, the biochemical parameters of the serum were not altered, and there was neither induction nor prevention of preneoplasic lesions.

Detection of omega-3 fatty acid in designer eggs using hyperspectral imaging

Quantification of n-3 polyunsaturated fatty acids (PUFA) is an important aspect in quality control of designer eggs. Prediction of these fatty acids would be of value for egg grading stations. The aim of the present study was to evaluate the ability of hyperspectral imaging (HSI) to classify the eggs according their content in n-3 PUFA as a rapid and non-destructive technique. Furthermore, HSI was used to predict the content of n-3 PUFA in designer eggs. Normal eggs, eggs containing 75 mg and eggs containing 125 mg docosahexaenoic acid were purchased from a grocery store. After hyperspectral transmittance images were collected in the spectral region of 900-1,700 nm, the eggs were broken and analyzed chemically in order to measure fatty acid content. Regions of interest (ROIs) of about 3,000 pixels from each egg were selected. K-means analysis was performed to classify eggs into the three aforementioned types. The classification accuracy was 100%. A partial least-squares regression model was built and used to link the ROIs with results obtained from the chemical analysis. The correlation coefficients between the measured and predicted values of alpha-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid were 0.94, 0.73 and 0.87, respectively. The root mean square error values for the validation sets were 38.65, 3.31 and 7.03, respectively. These results showed that HSI could be used both for discriminating the eggs between normal and designer eggs and for prediction of n-3 PUFA content in eggs.

Determination of alpha-linolenic acid and linoleic acid in edible oils using near-infrared spectroscopy improved by wavelet transform and uninformative variable elimination

This paper proposes an analytical method for simultaneous near-infrared (NIR) spectrometric determination of alpha-linolenic and linoleic acid in eight types of edible vegetable oils and their blending. For this purpose, a combination of spectral wavelength selection by wavelet transform (WT) and elimination of uninformative variables (UVE) was proposed to obtain simple partial least square (PLS) models based on a small subset of wavelengths. WT was firstly utilized to compress full NIR spectra which contain 1413 redundant variables, and 42 wavelet approximate coefficients were obtained. UVE was then carried out to further select the informative variables. Finally, 27 and 19 wavelet approximate coefficients were selected by UVE for alpha-linolenic and linoleic acid, respectively. The selected variables were used as inputs of PLS model. Due to original spectra were compressed, and irrelevant variables were eliminated, more parsimonious and efficient model based on WT-UVE was obtained compared with the conventional PLS model with full spectra data. The coefficient of determination (r(2)) and root mean square error prediction set (RMSEP) for prediction set were 0.9345 and 0.0123 for alpha-linolenic acid prediction by WT-UVE-PLS model. The r(2) and RMSEP were 0.9054, 0.0437 for linoleic acid prediction. The good performance showed a potential application using WT-UVE to select NIR effective variables. WT-UVE can both speed up the calculation and improve the predicted results. The results indicated that it was feasible to fast determine alpha-linolenic acid and linoleic acid content in edible oils using NIR spectroscopy.

Significance of coprophagy for the fatty acid profile in body tissues of rabbits fed different diets

Four groups of eight New Zealand hybrid rabbits were fattened with ad libitum access to the following pelleted experimental diets: ryegrass meal or alfalfa meal fed either alone or with oats meal in a ratio of 1:1. After 25 weeks they were slaughtered and dissected. Fatty acid (FA) profiles of caecotrophs (re-ingested fermentation products of the caecum), perirenal adipose tissue and intramuscular fat in the Musculus quadriceps were determined. With high proportions of branched-chain FA (BFA) and trans FA, and increased proportions of saturated FA relative to the diets, the caecotroph FA profile showed a clear fingerprint of anaerobe microbial lipid metabolism including biohydrogenation. By contrast, the FA profiles of adipose and lean tissue comprised high proportions of polyunsaturated FA (PUFA), whilst BFA and trans FA occurred in much lower proportions compared to the caecotrophs. Thus, coprophagy did not substantially modify the FA composition of the tissues investigated. Use of forage-only diets, compared to the oats supplemented diets, led to extraordinary high proportions of n-3 PUFA (including 18:3 and long-chain n-3) in the fat of adipose (21.3 vs. 6.7%) and lean tissue (15.4 vs. 5.7%). The forage type diet (grass vs. alfalfa) had smaller effects on the FA profiles. Indications of diet effects on endogenous desaturation, chain elongation and differential distribution of functional FA between the two tissues investigated were found.